The week began here on Swampland with Mark Halperin’s optimistic dispatch from Chicago, “Why The Obama Campaign Is Confident About Beating Romney.” So perhaps it is appropriate that the week get bracketed by a report by William Galston, a Democratic strategist who has worked for Bill Clinton, Al Gore and Walter Mondale, among others. His 25-page document, “Six Months To Go: where the Presidential Contest Stands as the General Election Begins” describes in remarkable detail the significant political headwinds that are likely to make this election among the closest and most difficult incumbent reelection efforts in modern history. He sums up the situation this way: “The Obama folks wanted a rerun of 1984, and this time if they are lucky they are going to get a rerun of 2004.” You should read the whole document (.pdf here). But in the meantime, some highlights, or lowlights as it were:

–Obama’s job approval “remains significantly lower than that of the past five incumbents who won their reelection contests and is actually two points lower than Jimmy Carter‘s was at this point in 1980.” One recent survey (Quinnipiac) found that “only 46 percent of the people think that Obama deserves to be reelected, versus 49 percent who do not.” According to a Fox poll, just 36 percent of country thinks Obama has a clear plan to fix the economy, which is marginally better than the 31% who think Romney has a plan.

–The mood of the country remains sour and fragile, though improved from the bottom it hit last summer. Are you better off than you were four years ago? According to Quinnipiac, 35% say yes, and 41% say no. Right track/wrong direction questions in various polls show that pessimists outnumber optimists by two to one, a moderate improvement from last fall but still not where an incumbent wants to be.

–On the issues, Obama holds some advantages, but his signature accomplishment, the Affordable Care Act is the victory that dare not speak its name. According to ABC/Wash Post, just 39 percent of Americans back the bill, while 53 percent oppose it. This means a significant share of the president’s own supporters–who will vote for him in November–are nonplussed.

–On enthusiasm, the polls have reversed from 2008, and Obama is now at a clear disadvantage, especially among core segments of his base, like young people and Hispanics. Forty-two percent of Republicans told Quinnipiac that they are more enthusiastic about this election than others, compared to just 28 percent of Democrats. And given a relatively low number of expected swing voters–about 23 percent of the electorate–enthusiasm is likely to make a big impact on the final election result.

–On ideology, Galston has a near perfect summary of the current state of play. “Both Obama and Romney are running as the tribunes of their party’s respective bases. That means that the election of 2012 will feature the widest gap between presidential candidates since at least 1984.” One could argue that this is an advantage for Obama, since many Republican positions are not popular in their particulars, but the opposite may in fact be the case. A recent Third Way report found Romney had a key advantage: Independents still distinguish him from his own party in a way that they do not for Obama. “Swing independents see President Obama and the Democratic Party as ideological twins, well to the left of where they place themselves on the ideological spectrum,” Galston writes. “By contrast, they see an ideological gap between Romney and Republicans, with Romney much more moderate than his party.”

Obama’s strategists argue, as they did to Halperin, that the coming months will allow Obama to eliminate this disadvantage, by defining Romney as an extremist who, by the way, has other negative qualities, like not understanding regular people or sharing their values. But this depends on the campaign not being a referendum on the president, but a choice between the two candidates. And that is still far from certain. As Galston observes, “When incumbents run for reelection, the contest is mostly about their record.” If Americans decide the record warrants reelection, there is nothing that can be done by the challenger to win. If Americans don’t like the incumbents record, the challenger only needs to prove that he is an acceptable alternative.

It is too soon to tell on which battlefield this election will be fought, but if the economy continues to falter with pressure from overseas, the latter is far more likely. And that is where Galston basically ends up his analysis: Conditions have unquestionably improved for Obama from six months ago. But it is what happens in the next six months that will likely matter more. As a result, world events beyond either candidates’ control will likely be far more influential than the daily tactical skirmish between campaigns. “Between now and November 6,” Galston writes. “it will be more important to monitor the monthly reports on jobs and income than to fixate on the daily tracking polls.”

That should be enough to put a damper on all of Chicago’s optimism. Their game plan, after all, needs some help from forces beyond their control.